How to setup sell additional web space?

[SplashyHost]

A customer has contacted me asking for more web space... he says he has ran out but not viable for him to upgrade his package.

 

I said I can offer additional 1GB priced at £X/month... However, after looking in the admin area I can't quite work out how to do it.

 

For example.. I want to allow my client to add on an additional 1GB for £1/month, he pays yearly so either bill him the full £12 upfront or add it pro-rata(?) to his package, so if he has 2 month left he would pay £2 today and then £12 on his next annual billing cycle.

 

What is the best way to do this?

 

Thanks

[WHMCS John]

Hi,

You could either use Product Addons or Configurable Options. Which you use depends upon whether you want to bill them up front or pro-rate it to their existing renewal date: http://docs.whmcs.com/Addons_and_Configurable_Options